In building construction particularly, board-shaped elements of construction are employed as part of the façade scaffolding. A plurality of application classes, defined by the size (width of the board), working load and intended purpose among other factors, are distinguished. Because a façade scaffolding is a temporary structure, these scaffoldings are usually of modular construction; that is, virtually any scaffolding design can be put up with a small number of uniformly constructed elements (ledgers, bearers, and boards).
The board-shaped elements of construction ordinarily have a length of 250 cm and a width between 60 cm and 90 cm. As a rule, they are used for all application classes. They experience loading primarily in flexure but, in addition, must also be able to handle individual concentrated loading cases.
Elements of wood, a wood-aluminum composite, aluminum, or steel are conventionally used for the boards. All these materials, however, have specific disadvantages.
Wood elements, for example, absorb water, which can lead to externally invisible rotting, in particular of the wood core, and unforeseeable fracturing of the board element. In order to avoid this sudden failure due to water absorption, such wooden boards must be inspected periodically. The lifetime or service life of such board elements is thus greatly limited. Water absorption further leads to a gain in the weight of these board elements, which on the one hand has a disadvantageous impact on the handling of the elements when scaffoldings are being erected or dismantled at the construction site and on the other hand increases the dead weight of the scaffolding, leading to a reduction in the working load.
In the case of composite or hybrid wood-aluminum boards, while the dead weight is reduced in comparison with the plain wood board, the same disadvantages in terms of water absorption are present as in the previous case. Along with the danger of failure due to water absorption, here there is a further possibility of failure of the welds in the aluminum frames.
Plain aluminum boards in comparison with composite or hybrid boards do not exhibit any major differences in terms of weight but are not susceptible to water absorption. Such boards, however, have very poor fatigue properties with respect to the danger of failure of the welds, which again means that the lifetime is limited. Boards currently available on the market also have a low resistance to skidding, which has a disadvantageous impact on safety.
All conventional boards have a high specific weight, which has a disadvantageous impact particularly on handling, that is, assembly, dismantling, transport and storage.
In order to address these disadvantages, trials with alternative materials have also been carried out. In particular, boards have been fabricated from fiber-reinforced plastic, which led to lower weights and better environmental stability in comparison with conventional boards. As a rule, however, plastics exhibit an unfavorable modulus of elasticity, so that either the required properties could not be attained or else very thick boards resulted.
Thus from DE 37 05 566 there is known a facade scaffolding having such a board having narrow, downwardly extending flange surfaces along two opposite sides, the board having longitudinal and/or transverse fins on its underside. In order to attain adequate strength, however, these boards need a steel frame arranged thereunder and having ledgers on which the lateral edges of the boards or the flange surfaces can rest.